Card Set Information

2011-02-24 18:21:48

Bio II Midterm 1
Show Answers:

  1. infectious diseases account for...
    nearly 30% of all worldwide mortality; mostly in developing countries
  2. decreases in infectious cases (3):
    1) sanitization, 2) vaccination (small pox, totally irradiated), and 3) antibiotics (by Flemming, but obviously don’t work against viruses)
  3. virus
    not cells, but obligate intracellular parasites; are very small infectious particles consisting of nucleic acid enclosed in a protein coat and, in some cases, a membranous envelope; genome can consist of DNA or RNA; dissasemble during reproductive cycle
  4. Mimivirus
    largest viral genome, infects amoebas, 1000 Mb
  5. capsid
    protein shell that encloses the viral genome; can have various (rod-shaped [helical], or icosahedral) structures; built from capsomeres (protein subunits)
  6. membranous envelopes
    some have membranes derived from the membranes of host cells; they surround capsids; fools host's immune system by allowing virus to remain undetected; also facilitates fusion of hte virus wiht the host cell membrane
  7. virus makes use of host's...(6ish things)
    1) enzymes, 2) ribosomes, 3) tRNAs, 4) amino acids, 5) ATP, 6) other molecules
  8. RNA viruses
    broadest variety of RNA genomes is found in viruses that infect animals; retrovirus (class of RNA virues) that use reverse transcriptase to copy RNA genome into DNA
  9. HIV (human immunodeficiency virus)
    the retrovirus that causes AIDS (acquired immunodeficiency syndrome); contains a capsid with two identical strands of RNA and reverse transcriptase, a glucoprotein outer layer, and a viral envelope
  10. provirus
    a viral DNA integrated into the host DNA
  11. prophage
    phage inserted into bacterial genome
  12. nucleoside analogs
    a range of antiviral products used to prevent viral replication in infected cells; they work by terminating viral DNA Polymerase; ex: AZT
  13. vaccines
    harmless derivatives of pathogenic microbes that stimulate the immune system to mount defenses against the actual pathogen; ex: Jenner injected the less serious cowpox which prevented the contraction of similar but fatal smallpox
  14. viroids
    circular RNA molecules that infect plants and disrupt their growth
  15. prions
    slow-acting, indestructible infectious proteins that cause brain disease in mammals; propogate by converting normal proteins into the prion version
  16. bacteriophages
    also simply known as phages, are viruses that infect bacteria; MOST complex capsids found in viruses; have an elongated capsid head; protein tail piece attaches the phage to the host and injects phage DNA inside
  17. lytic cycle
    phage reproductive cycle that culminates in the dealth of the host cell; virulent phage is one that only reproduces by the lytic cycle
  18. lysogenic cycle
    allows replication of the phage genome without destroying the host; the viral DNA molecule is incorperated into host chromosome; temperate phages are phages capable of using both types of reproduction within a bacterium
  19. restriction enzymes
    bacteria's defense against phages, cuts up phage DNA when they recognize it as foreign
  20. transformation
    the genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings
  21. transduction
    bacteriophages carry bacterial genes from one host cell to another; example of horizontal gene transfer
  22. conjugation
    genetic material is transfered between two bacterial cells that are temporarily joined by sex pili; result of F (fertility) factor